This present invention relates generally to manufacturing objects. More particularly, the invention relates to a method and structure for fabricating electrical connections for spatial light modulators. Merely by way of example, the invention has been applied to the formation of an electrical connector running from a bias grid on a substrate to a reflective surface deposited on a mirror structure. The method and structure can be applied to spatial light modulators as well as other devices, for example, micro-electromechanical sensors, detectors, and displays.
Micro-electromechanical systems (MEMS) are used in a number of application areas. For example, MEMS have been used in micro-mirror arrays, sensors, and actuators. In some of these applications, a suspended member is supported by a flexible hinge attached to a stationary portion of the mirco-mirror array. Flexibly attached to the hinge, the suspended member is attracted to an electrode upon application of an electrical force and restored to an original position by a restoring force. In this manner, the array of micro-mirrors can be tilted in relation to a light source. In some applications, the suspended member is coated with a reflective surface to increase the reflectivity of the array of micro-mirrors. Furthermore, in some applications, it is beneficial to have the suspended member electrically coupled to a source of electrical current to facilitate the application of the electrical force and prevent static charging of the suspended member.
As merely an example, conventional MEMS have utilized various electrical connector schemes to couple the suspended member to a source of electrical current. For example, some micro-mirror designs utilize a single electrical connection at an outer edge of the micro-mirror array that is distributed over the array through a series of connectors. Unfortunately, these techniques also have limitations. For example, an extended current path may result in propagation delays that can adversely impact the response time of individual elements of the MEMS array. Therefore, there is a need in the art for methods and apparatus for fabricating electrical connections for spatial light modulators.